totalCountHint incorrectly set by API for multi-part refresh

The documentation for RsslMap indicates totalCountHint should contain an approximate total for the entire map across a multi-part response. When specifying a hint of zero or none at all the library automatically fills in the count of each single refresh instead. Is this expected?

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elektron

caching

elektron-sdk

elektron-transport-api

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Accepted answers

Jirapongse

totalCountHint is optional and API should not be able to set its value because it couldn't know the total number of entries across a multi-part response sent by the application.

I believe that the application see the incorrect value because it doesn't verify its presence before accessing it. In UPA, the application should check a RSSL_MPF_HAS_TOTAL_COUNT_HINT flag before accessing the value of totalCountHint.

All comments

Jirapongse

totalCountHint is optional and API should not be able to set its value because it couldn't know the total number of entries across a multi-part response sent by the application.

Steven McCoy

The hint count is being set as I have fed the message through the value-add payload cache.

Jirapongse

From my test, I found that the value-add payload cache can update totalCountHint properly for the multi-part refresh message.

I sent these three part refresh messages and apply those message to cache.

<refreshMsg domainType="RSSL_DMT_SYMBOL_LIST" streamId="400" containerType="RSSL_DT_MAP" flags="0x11A8 (RSSL_RFMF_HAS_MSG_KEY|RSSL_RFMF_SOLICITED|RSSL_RFMF_HAS_QOS|RSSL_RFMF_CLEAR_CACHE|RSSL_RFMF_HAS_PART_NUM)" groupId="0" partNum="0" qosDynamic="0" qosRate="1" qosTimeliness="1" dataState="RSSL_DATA_OK" streamState="RSSL_STREAM_OPEN" code="RSSL_SC_NONE" text="Item Refresh Completed"  dataSize="24">
    <key  flags="0x3 (RSSL_MKF_HAS_SERVICE_ID|RSSL_MKF_HAS_NAME)"  serviceId="1" name="_UPA_ITEM_LIST"/>
    <dataBody>
        <map flags="0x0" countHint="0" keyPrimitiveType="RSSL_DT_BUFFER" containerType="RSSL_DT_NO_DATA" >
            <mapEntry flags="0x0" action="RSSL_MPEA_ADD_ENTRY" key="TRI" >
            </mapEntry>
            <mapEntry flags="0x0" action="RSSL_MPEA_ADD_ENTRY" key="RES-DS" >
            </mapEntry>
            <mapEntry flags="0x0" action="RSSL_MPEA_ADD_ENTRY" key="MING" >
            </mapEntry>
        </map>
    </dataBody>
</refreshMsg>

<refreshMsg domainType="RSSL_DMT_SYMBOL_LIST" streamId="400" containerType="RSSL_DT_MAP" flags="0x10A8 (RSSL_RFMF_HAS_MSG_KEY|RSSL_RFMF_SOLICITED|RSSL_RFMF_HAS_QOS|RSSL_RFMF_HAS_PART_NUM)" groupId="0" partNum="1" qosDynamic="0" qosRate="1"qosTimeliness="1" dataState="RSSL_DATA_OK" streamState="RSSL_STREAM_OPEN" code="RSSL_SC_NONE" text="Item Refresh Completed"  dataSize="26">
    <key  flags="0x3 (RSSL_MKF_HAS_SERVICE_ID|RSSL_MKF_HAS_NAME)"  serviceId="1" name="_UPA_ITEM_LIST"/>
    <dataBody>
        <map flags="0x0" countHint="0" keyPrimitiveType="RSSL_DT_BUFFER" containerType="RSSL_DT_NO_DATA" >
            <mapEntry flags="0x0" action="RSSL_MPEA_ADD_ENTRY" key="MING1" >
            </mapEntry>
            <mapEntry flags="0x0" action="RSSL_MPEA_ADD_ENTRY" key="MING2" >
            </mapEntry>
            <mapEntry flags="0x0" action="RSSL_MPEA_ADD_ENTRY" key="MING3" >
            </mapEntry>
        </map>
    </dataBody>
</refreshMsg>

<refreshMsg domainType="RSSL_DMT_SYMBOL_LIST" streamId="400" containerType="RSSL_DT_MAP" flags="0x10E8 (RSSL_RFMF_HAS_MSG_KEY|RSSL_RFMF_SOLICITED|RSSL_RFMF_REFRESH_COMPLETE|RSSL_RFMF_HAS_QOS|RSSL_RFMF_HAS_PART_NUM)" groupId="0" partNum="2"qosDynamic="0" qosRate="1" qosTimeliness="1" dataState="RSSL_DATA_OK" streamState="RSSL_STREAM_OPEN" code="RSSL_SC_NONE" text="Item Refresh Completed"  dataSize="19">
    <key  flags="0x3 (RSSL_MKF_HAS_SERVICE_ID|RSSL_MKF_HAS_NAME)"  serviceId="1" name="_UPA_ITEM_LIST"/>
    <dataBody>
        <map flags="0x0" countHint="0" keyPrimitiveType="RSSL_DT_BUFFER" containerType="RSSL_DT_NO_DATA" >
            <mapEntry flags="0x0" action="RSSL_MPEA_ADD_ENTRY" key="MING4" >
            </mapEntry>
            <mapEntry flags="0x0" action="RSSL_MPEA_ADD_ENTRY" key="MING5" >
            </mapEntry>
        </map>
    </dataBody>
</refreshMsg>

The following is the message that I got from cache.

<refreshMsg domainType="RSSL_DMT_SYMBOL_LIST" streamId="400" containerType="RSSL_DT_MAP" flags="0x1E8 (RSSL_RFMF_HAS_MSG_KEY|RSSL_RFMF_SOLICITED|RSSL_RFMF_REFRESH_COMPLETE|RSSL_RFMF_HAS_QOS|RSSL_RFMF_CLEAR_CACHE)" groupId="0" qosDynamic="0" qosRate="1" qosTimeliness="1" dataState="RSSL_DATA_OK" streamState="RSSL_STREAM_OPEN" code="RSSL_SC_NONE" text="Item Refresh Completed"  dataSize="60">
    <key  flags="0x3 (RSSL_MKF_HAS_SERVICE_ID|RSSL_MKF_HAS_NAME)"  serviceId="1" name="_UPA_ITEM_LIST"/>
    <dataBody>
        <map flags="0x8 (RSSL_MPF_HAS_TOTAL_COUNT_HINT)" countHint="8" keyPrimitiveType="RSSL_DT_BUFFER" containerType="RSSL_DT_NO_DATA" >
            <mapEntry flags="0x0" action="RSSL_MPEA_ADD_ENTRY" key="MING" >
            </mapEntry>
            <mapEntry flags="0x0" action="RSSL_MPEA_ADD_ENTRY" key="MING1" >
            </mapEntry>
            <mapEntry flags="0x0" action="RSSL_MPEA_ADD_ENTRY" key="MING2" >
            </mapEntry>
            <mapEntry flags="0x0" action="RSSL_MPEA_ADD_ENTRY" key="MING3" >
            </mapEntry>
            <mapEntry flags="0x0" action="RSSL_MPEA_ADD_ENTRY" key="MING4" >
            </mapEntry>
            <mapEntry flags="0x0" action="RSSL_MPEA_ADD_ENTRY" key="MING5" >
            </mapEntry>
            <mapEntry flags="0x0" action="RSSL_MPEA_ADD_ENTRY" key="RES-DS" >
            </mapEntry>
            <mapEntry flags="0x0" action="RSSL_MPEA_ADD_ENTRY" key="TRI" >
            </mapEntry>
        </map>
    </dataBody>
</refreshMsg>

The total count hint is set properly.

Steven McCoy

But can I extract a multi-part refresh from a single large payload cache?

Jirapongse

Refer to UPAValueAddDevGuide.pdf, you can get a multi-part from the cache.

9.3.3.1 Multi-Part Retrieval

...

For multi-part retrieval, the application makes
a series of calls to rsslPayloadEntryRetrieve to get the OMM container in fragments (e.g. a sequence of maps are
retrieved which together contain the entire set of map entries for the OMM container). In this usage, the optional
RsslPayloadCursorHandle is required to maintain the state of the multi-part retrieval.

Steven McCoy

Wow, great, thank you very much.

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